Python/project_euler/problem_020/sol4.py

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"""
Problem 20: https://projecteuler.net/problem=20
n! means n × (n 1) × ... × 3 × 2 × 1
For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
Find the sum of the digits in the number 100!
"""
def solution(num: int = 100) -> int:
"""Returns the sum of the digits in the factorial of num
>>> solution(100)
648
>>> solution(50)
216
>>> solution(10)
27
>>> solution(5)
3
>>> solution(3)
6
>>> solution(2)
2
>>> solution(1)
1
"""
fact = 1
result = 0
for i in range(1, num + 1):
fact *= i
for j in str(fact):
result += int(j)
return result
if __name__ == "__main__":
print(solution(int(input("Enter the Number: ").strip())))